A conventional electromagnetic actuator for opening and closing a valve of an internal combustion engine generally includes "open" and "close" electromagnets which, when energized, produce an electromagnetic force on an armature. The armature is biased by a pair of identical springs arranged in parallel. The armature is coupled with a cylinder valve of the engine. The armature rests approximately half way between the open and close electromagnets when the springs are in equilibrium. When the armature is held by a magnetic force in either the closed or opened position (at rest against the open or close electromagnet), potential energy is stored by the springs. If the magnetic force is shut off with the armature in the opened position, the spring's potential energy will be converted to kinetic energy of the moving mass and cause the armature to move towards the close electromagnet. If friction is sufficiently low, the armature can then be caught in the closed position by applying current to the close electromagnet.
The conventional electromagnetic actuator has a one-piece housing which is constructed and arranged to contain the core or lamination stack for an electromagnet. It is often the case that the lamination stack height may vary for each electromagnet since the laminated core assembly is composed of many individual laminations each having a certain height dimension within a predetermined tolerance. In certain instances, tolerance stack-up of the many laminations may not permit the overall lamination stack to fit easily within the one-piece housing.
Accordingly, there is a need to provide an electromagnetic actuator having a housing assembly configuration which accounts for varying lamination stack heights to facilitate assembly of the lamination stack with respect to the housing assembly.